Maybe, I testing it out now on a 3gs had only done the 3g so far(which is the same) since my 3gs is already on 4.1 with snowbreeeze. So maybe they got lazy and decided to put all 3gs owners in the same boat to try to make it fool proof for people who don't know if they've been pwned or if they are new or old bootrom. Because there is no reason to switch exploits especially considering the new one is a teather without the kernel exploit which can/will be fixed.
"Through a combination of the recently released geohot limera1n exploit , @comexs recently released pf kernel exploit, and our original pwnage2 exploit, PwnageTool 4.1 4.1.1 works untethered on these devices at firmware 4.1:"
With that above and a mention that people on the train would stay on it with 4.1 it's not a huge leap to see that they dropped the ball for 3gs owners.
yeah, the 3GS is running the new exploit while the 3G has the same older exploit as before. Which is sad because I lost my custom boot logos this time around and is not as good as exploit as the original one.