Yes, but it can be 7, 8, or 9-spd cogs, as long as they can be separated into individual cogs (less likely with 9-spd). If riveted together, the rivets can be drilled out pretty easily. More typically they're connected as sold with long skinny bolts with either a small external hex, or tiny internal hex at the back. (The tool that is used to hold chain ring nuts has a socket that perfectly fits those external hex bolts.) The cog thickness is the same for all of those. Difference is in the spacers. BTW, the outer-most cog often has a built-in spacer, but no worries on that since shifting at that end is only affected by the H limit screw. So 8 or 9-spd would be preferred there, since they're skinnier.

What doesn't work with this conversion are cassettes where several cogs are joined on a spider, which is used much more on 9-spd, and on a few 8-spd cassettes.

I've built up a collection of loose Shimano cogs by purchasing used but good condition cassettes at co-ops and used bike part emporiums, and inexpensive new 7-speed cassettes.

Loose cogs and separate lockrings are also available, and I've used those from Miche to fill in gaps in my collection. Typically the Miche lockrings from the linked source below seem to be a bit taller (another thread longer).

https://www.universalcycles.com/shop...?category=1569