It’s rare that Apple sell 2 generations of the same line simultaneously for long on the refurb store. The revised price will probably remain until Apple no longer sell it. The only other way there would be a price change would be due to an exchange rate change that the Apple hedge didn’t account for, that will usually spell a price increase for euro customers.They likely won't be sold for $300 on the refurb store. What Apple generally does is just remove them from the store completely at a certain point.
Anyhow at this point, that price difference is minimal. Even if the price did drop (but it likely won't), if you needed a Mac soon, $319 now seems to make much more sense than waiting until 2026 to get it for $299.
But it's too late, since it's sold out now. It might come back in a few weeks though, who knows.
The price correction on the m2 will have been welcome but if you need one then the 319 usd base model is the sweet spot there. As you add extra storage and ram onto the older model the m4 model becomes the wiser buy on account of the fact it has 16Gb ram as standard. There’s also the issue of the 256gb storage models being hamstrung by the slow nand module from the m2 generation.
My forecast will be that we might see m2 refurbs on sale occasionally in the Apple refurb store in the short to medium term but at some point quite soon they will no longer be offered.
Basically, if you need 16Gb ram in your refurb then get the m4. If your use case is extremely light and a relatively slow 256gb ssd module doesn’t bother you then the base model m2 seems ok.