Bolt patterns. 76 Chevy RV chassis?

[Frank]

I have a set of 6 wheels from a 76 Winnebago that all hold air, but the tires are very old and they are split ring rims. We swapped modern wheels on the rig and I just want to get rid of them. I figure all they are good for is an old farm truck or rollers for some project. I know nothing about large patterns like this. I don't have any pics, but I think they are 10 lug last I saw them? (not at my house).

Does anyone know if these fit across several makes? For some reason I thought Ford/Chevy/Dodge whatever all use the same pattern when they get this large. Anyone know?