The 521-T is a GREAT rifle, and that's a very good price for one. Nice to see that you have the original Lyman sights, as well. For the time it was a very good sight.
My Dad bought himself a 521-T when he was a kid, late 1940s or early 1950s. It's the rifle I learned to shoot on. It's also one of the few rifles that I would never, under any circumstances, part with.
Many years ago I found a batch of PMC Lightning ammo that was a laser beam out of it, cutting close to 1" groups (Lyman iron sights) at 50 yards.
In the mid 1980s my Mom picked up a Weaver C-4 rimfire scope at a yardsale for $1, so I had it mounted. Made an a great gun even better.
Yours is in better shape. Dad used his a tremendous amount, and most of the finish is gone. I didn't help it with the amount that I've used it. It's honest wear, though.