Just wondering, have there been any MX-fit F-keys (ie, function row, not letter F) in red with white text?

Like this:

Yes, from some Access IS POS board. Pics from my collection:

Thanks - that Esc looks lasered, but what are the others? My next question/s is/are, how easily obtainable are these caps, and is 1-12 standard or are there other boards with more/fewer?

The ESC and most other keys are engraved, and filled. Same contrast as double shots. The F-Keys are actually double shot. I have seen the boards a couple of times on eBay, but they are probably more on the rare side of access boards.