I highly doubt it. Once Apple announces the date for their quarter report, this time July 20th, don't expect anything until AFTER that date. It could occur next Wednesday, but I also wouldn't hold my breath on that either.
They could do it on the same day if don't wait till market closes to release the numbers. Lots of info will be released that day. Even more so since it would not be a "big dog and pony show release". Being quiet before the quarterly report would be more a reason to move it off of today, 13th, much more than the same day. The Mac Pros sold that day have absolutely zero material impact on the FYQ3 numbers that Apple is going to talk about (as they would now). FYQ4 has already started for a couple of weeks. That revenue won't show up until a discussion in October. The number of Mac Pros that they could sell in a couple of hours would have zero impact on their FYQ4 projections. So really makes no difference in the financial discussions.
The SEC restrictions are talking about the financial results. They are not on releasing product if it is time.
Frankly a release that morning of a Mac Pro would avoid someone perhaps bringing up "Are you dumping the Mac product lines" kinds of questions.
That said I personally think the obvious hang up is that Intel hasn't shipped 3620 and 3640 processors. Without them not going to get a Mac Pro update.
If Intel announces their availabiity on the 19th and Apple doesn't move on the 20th that is a screw up. Not sure if Intel is going to wait till August though to let those loose on the market. ( there is a big i7-960 price cut rumored to be coming in August. That should help open the door for a $600 six core processor. )
Based on the reports, I think we will see the iMac, Mac Pro, and new Cinema Display make an appearance in August. If not, I can see it happening in October or November at a desktop focused event based with a new iLife/iWork.
Folks wanting some big dog and pony show event are likely in for deep disappointment. The personal computer market is quite mature now. There is no need for nor big impact of big dog and pony show events by single vendor. The primary product category that the Mac Pro and iMac fill have been out for over a decade. It is going to be an incremental update and it isn't some fad "this christmas is pink" trend. Trying to pin Mac releases to circus events is folly.
It would be whacked to update the upped end iMac on Lynnfield stuff when Sandy Bridge options are likely going to drop in Q4. Sure the low end could leverage some Clarkdale stuff that is already out, but that is just dual core, high GHz stuff. That isn't necessarily close to multicore workload work that is Mac Pro centered. There is not much synergy there to couple the two. If Apple did roll out the revamped Lynnfield/Clarkdale stuff they'd be sticking with that for long time after the Sandy bridge stuff went mainstream. If waiting from Aug to late Oct gets you a whole new micro arch at price point can use.... why? Just because have to release in less than 12 months? Don't make much sense from a long term perspective. If the desktop, no IGP, quad core Sandy bridge are going to be too expensive I can see it happening in Aug/Sept. , but otherwise would make more sense to update iMac on 12 month schedule that matches Intel's updates.
Displays...... Eizo , NEC , Dell, HP all seem to be proceeding with higher end displays (some with 10bits and/or 3D LUT ) without Apple's participation. The LED backlight with 27" display still seems to be something Apple hasn't completely nailed down on the iMac. Extremely unlikely, that the Mac Pro crowd would put up with that. The only primary thing Apple needs are 10bit output cards certified on the Mac Pro. The "mainstream" 27"-30" monitor at this point is just commodity play with very little upside. Even more so if going to restrict to just to single display port interfaces (or worse mini display port) .