[Aladdin]

The filler screws can be found here.
http://shopruger.com/B-83-SS-MK-I-II-III-Scope-Base-Filler-Screws-SS-61134/productinfo/61134/

Or here the 10/22 screws will work and are less money.

http://shopruger.com/C-83-10_22-Stainless-Set-4-Filler-plug-Screws/productinfo/60045/