Yeah, I never noticed any functional difference at all either, but to each their own lol. Will also gladly take the bolt shroud and recoil lug upgrade and the ability to use the vertical grips etc on the new stock though.
I did just that with my T3 stainless 308. I think we've talked about that rifle before. Factory stocks are very cheap and easy to find. An upgrade to a T3x stock from a T3 stock is a good thing. I'm like the OP, I found my T3 308 for cheap, and bought it, without hesitation though.
It was also $500.00, but it came with a nice Bushnell elite 3200 3-9x40. I didn't need the scope, so later sold it for $230.00. I also sold the hideous Tikka factory rings for $35.00. So, well into the rifle for way under $500 now. Now it sits in a takeoff T3x stock, and suits my needs just fine:
It's a shooting machine. It shoots almost as good as my heavy barreled model 70, but weighs about 3 pounds less. There's beauty in a lightweight tack driving hunting rifle.