Skaer,
1. Your last post was essentially correct--if it is marked T or TC, get it, or get it if it already has the parts attached (try to get a letter that says it was put together that way before the '97 thing).
2. The SR-9 is polygonal, the 911 is standard rifling.
3. The Springfield (not the more recent aluminum receiver guns) are marked either SAR-3 or SAR-8. The SAR-3 was a pre-ban Greek made gun (HK contract company). The SAR-8 was a Greek made post ban (no flash hider, and a thumbhole). You may RARELY find a gun marked on one side with a -3 and on the other with a -8, these were caught in the middle of the 89 ban, and MAY be legal with the flash hider and pistol grip if it was installed before Nov. '90. Any aluminum receiver gun is post ban, and needs to have a certain amount of US parts along with the G-3 parts used to build it (it can have a pistol grip, but no flash hider). If you find an SAR-3 for $1100, you could sell it for $500 profit almost immediately.
4. The 911 rifles were HK 91's that got caught up in the ban. They removed the flash hider, put a thumbhole stock on, and stamped it with an extra "1" to get around the California ban on specific rifles. Then they brought out the SR-9 series. The T and TC stamped on the SR-9's were stamped on AFTER import, so the stamping doesn't quite match.
AFARR