Shelly Manne & His Men ‎– At The Black Hawk vinyl

I have loved this set of LPs for ages, but started some research on the lineage to discover what might be the best sounding version(s). The original mono pressings command a pretty large sum, but I keep my eyes open. I did happen upon the whole set for $4 each, they would appear to be late 60s stereo reissues, but figured I couldn't go wrong.

Doing some research on the deadwax and searching online has helped some, but there are still some questions.

Not sure how concise this site is, but it claims the yellow-label stereo (which I have) is a 60’s era reissue, yet the deadwax is confounding, listing SLM (likely Sheffield Lab Matrix), which did not exist until 1979? 

This site is a very nice source on the history of Contemporary, Lester, and the Black Hawk sets, and on it mentions: "Early pressings had green and black labels. They also can be recognized by the machine stamped matrix number in the dead wax. For stereo discs the reference began with LKS, meaning Lester Koenig Stereo. The newer editions had the matrix numbers written by hand."

So, here is what I have on my pressings:

At The Black Hawk 1 [120 gram]

• Side 1: LKS-133 D6 + SLM + △283 40102-A SM#1 7577A #2
• (etched, except for “SLM" is stamped)
• Side 2: LKS-134-D6A + SLM + △569 7577-B 40102-B SM#1 #2
• (etched, except for “SLM" is stamped)

At The Black Hawk 2 [106 gram]

• Side 1: LKS-135 D4 + SLM + △ 932
• (all etched)
• Side 2: LKS 136 D4 A5 1 S
• (A5 1 S is etched,  "LKS 136 D4" is machine stamped)

At The Black Hawk 3 [128 gram]

• Side 1: LKS 137-D3 + SLM + △306 39328-A SM#1 7579 #3
• (etched, except for “SLM" is stamped)
• Side 2: LKS 138 D4 #4 39328-B SM#1 7579 AB S
• (etched, except for “SLM" is stamped, and the “A” in “AB” is scratched over)
• The band name and album title in the middle of the label are in a bold ALL-CAP font, unlike the others.

At The Black Hawk 4 [135 gram]

• Side 1: LKS-139-D7A #3 40479-A-SM#1 + SLM △ 1881
• (all etched)
• Side 2: LKS-140-03 #2 40479-B SM#1 + SLM △ 1880
• (all etched)

So, pretty sure I have a 60s reissue set and that somehow Vol 3 has the different font on the label which is consistent with the 70s labels, but the wrong color, and the weights are just all over the map!

If you know more, please, share your knowledge!