Stock wheel; which wheel is correct for 1961 GMC?

[MusicMan70]

I have four 15 x 5 (5" wide) 6 lug steel wheels. However one looks a little different and I'm wondering if it's an earlier or 50's wheel.

The first one has 3 clips, a gap/ridge/landing all around the center, before it meets the wheel rim; and four little "notches" on the outer rim itself.

The other has 6 clips, no notches and "meets" the rim directly.

I'd thought I read on another thread that there was a 15" wheel option(LT-1 Burb?), but have not been able to find it.

This restored 1960 appears to have the two different wheels as well.

Which wheel would be correct for a 61 GMC?

Here are the wheels and thanks for any and all replies: