I have a 1993 Ranger extended cab and from what I am reading the regular cab has the regular style rubber seal for the back window while the extended cab has the screw in style back window. Problem is that my extended cab has the regular rubber seal. I realized this after I bought a screw in style rear slider for my truck. Is it possible to install a screw in style in a truck that had the old style seal?

 

Then you have a early 1993 using a 1992 window, look at your "Build date" on the drivers door label
1993-2011 extended cabs all used the same size bolt in window, they added 2 extra studs in 2005 or 6

No, can not convert, the non-bolt in should be slightly smaller than the bolt in, you have both measure them to see