Will these fit? (Wheels)

[Catch_22]

I have a 67 with disc conversion installed on the front, still drum in the back.
I really want to part ways with the 22 inch wheels that came on my truck when I bought it and put some 15 inch smoothies on it. It seems these should fit ok based on my research but I wanted to ask to be sure, would I have any issues installing the below without any spacers/etc? Thanks, I would hate to pay return shipping on wheels.

To further expand on this, I have a 6 lug setup and I don't really understand backspacing and offsetting.

Front
Size: 15'' x 8''
Bolt Pattern: 6 x 5-1/2''
Rear Spacing: 4-1/4''
Offset: -6mm

Back
Size: 15'' x 10''
Bolt Pattern: 6 x 5-1/2''
Rear Spacing: 4''
Offset: -32mm