It is perhaps worth noting that, I believe it's possible to create a romset for any version of MAME, by using the latest romset, the latest "rollback" romset, a DAT file from the version of MAME you need a set for, and a tool like ClrMamePro.
I agree I think it's worth noting and worth bothering to learn to use the tools depending on your setup. With current MAME and the rollback sets you can build any version of MAME from the beginning of development for RetroPie or other projects outside the RP scope.
You can build partial or full sets which is handy if using multiple cores with "Arcade" for RetroPie and only need a few games from a specific ROM set or a few per core.
It works fine for vanilla MAME to just get the set from whatever source. If using mame2003-plus or fbneo who's rom sets are ever changing it's a big plus to know the tools but you'll still need to track down some miscellaneous or decrypted ROMs that may not included in the official MAME set when rebuilding.
I find it easier to grab the current DAT once in a while for a changing core to complete a set vs. following every commit to grab the added/updated ROMs.
Also mame2003-plus has the source driver files in the DAT which allows you to build subsets like neogeo only or cps1, cps2, cp3 or whatever combination you want. Now if we could only have the region information.
Along with the rollback CHDs you can include those also in your sets too which is usually v3 with the older cores. A few games with CHDs run acceptably on the Pi 4.
Mame2003-plus has support for UNIBIOS up to 4.0 if you have a need, want to tweak a setting or experiment, it's a core option.