Did you do a GOOGLE search?I did and here is what I found:https://www.vintagegunscopes.com/fixedpower3-4and7-8/weaver-d4-with-rings-c1970-84-crosshairhttps://www.thehighroad.org/index.php?threads/anybody-remember-weaver-d-4-scopes.258485/https://www.rimfirecentral.com/forums/showthread.php?t=463418-Y
I have a couple of the little Weaver scopes. A D6 that came with a Crosman 3100, made by Cometa, I bought from Baker. I also have B4 that came on a Philippine co2 rifle I also bought from baker. The turret caps are missing of the B4. They are both similar and work fine. The field of view is of course kinda' small. The D6 has two piece rings, the B4 a one piece mountAs far a vintage look and nostalgia they look great. You can find lots of them on line, especially eBay, for reasonable prides. Some are a little high.If they don't have little mounts, I had a little Daisy in 1 inch rings with a set of one inch to 3/4 inch adapters. 3/4 and 7/8 is not a lot of difference.