At last, I have decided to buy it. Seller said it was from 60s. I really don't know, so I'd appreciate your comments and insights. It is 16" and weighs 1580 grams. It is not keyholed, but the hole is pretty big - 14 mm.
Stamp:
[IMG]http://img215.imageshack.us/img215/2941/stampz.jpg[/IMG]
Hole. Notice the strange lathing around it. At first I thought the hole was enlarged by previous owner, but it seems to be perfectly smooth on the bottom side and it is in center of the bell, so the lathing is just unsymetrical.
[IMG]http://img215.imageshack.us/img215/4963/hole.jpg[/IMG]
Top side:
[IMG]http://img215.imageshack.us/img215/9117/frontfa.jpg[/IMG]
Bottom side:
[IMG]http://img215.imageshack.us/img215/9401/backao.jpg[/IMG]
I got it for 35 dollars.
(Oh, and thanks to Drumaholic for previous pricing!)