As you noted there are two version of this board, rev 1 and rev 3 (you have rev 1, you said.) There are always reasons that board revisions are done... Still doesn't mean that your board won't support an FX, however. There could be something relative to the board's power handling that was upgraded in rev 3 to handle FX cpus, who knows? But something was improved/corrected, no doubt about that.
It's worth remembering that the bios update doesn't "enable the AM3+ socket"--the board has had that from day one. What the update does is enable the board to support the AM3+ FX cpus...which is an entirely different proposition.
As AMDforME mentioned, NewEgg tests your cpu by putting it in a supporting board and if it runs and passes whatever diagnostic tests they run, they send it back--and that's a *good thing* as it allows you to know for certain that your cpu is OK and lets you mark it off your list. However, Newegg may or may not (probably not) test it in your revision (or even brand) motherboard. They probably would not do this unless you bought both from them in a combo deal--in which case Newegg is obligated to test both. But it doesn't sound like you purchased these components at the same time from Newegg.
So, your cpu is working correctly. That leaves only the motherboard. The ram is certainly a possibility, so you should put at least one DIMM of something else in there just for testing purposes. If your ram needs swapping then the board & cpu will run with the replacement ram--IF NOT, then although it by no means is certain, you should be looking at the motherboard. If you like this board then get another, by all means, but specifiy *revision 3.* That's just one more item you can check off.
I sympathize! This is like lego blocks and you shouldn't have these problems. I bought my ram and motherboard and cpu separately and they all came together and worked first time and have ever since! Good luck.
Win8.1 x64, UEFI install, version 2.6
FX-6300 @4.5GHz, stable, Turbo disabled, C&Q Enabled
8-gigs 1600MHz DDR3,2x4, 225fsb, 1800MHz effective, 1.5v
Boot: Seagate 320GB; WD 1TB Blue;2x500GB Barricudas=1TB RAID 0
Radeon HD 7850 2Gig
Lian-Li PC-V1200 case
Corsair 600W PSU, 1x 49a 12v rail