> However, that doesn't necessarily fix the issue of the machine that hasn't been
> patched in months. It might be possible to use that media to patch it to current, but
> I don't know if that's even possible - and, if it is, I doubt that it would let you
> pick & choose the updates to apply.
It is possible. I recently resurrected my 2011 ASUS 17" battlestation/laptop - it had last been used with gold master Win 10 and it got put in a closet because 5400 RPM drives + Windows 10 = pain. I swapped the boot drive for an SSD and added an 802.11ac USB dongle and then updated it to latest with the install media (if you download it on a Win10 system it gives you an option to just use it directly to update the machine without writing it to media).
You can't choose which updates you get, but you're fully up to date after doing it, as advertised.
What kind of surprised me is that that machine plays games OK - it's got a 1080P display and an Nvidia 460M GPU but it can play GTA V at better than console quality and better than console framerates even though on first launch it warned that the CPU was too weak (quad-core Sandy Bridge i7). For MAME it gets embarrassed by my Haswell-powered MacBook Air though.