I'd put it more like this:
Bootleg - A fake, a knockoff for any non-legal intent or purpose of an original product
Repro - A legitimized new or first run of a game from yesteryear with the blessing of the original IP owner (or current if they bought the rights)
Conversion - A fake, still illegal, but it's converted as the user end appears new, but the internal guts end up still being legally owned code you don't own nor did the conversion artist(s)
I get pissed seeing the lie of repro used in the Nintendo circles to legitimize their shitty thievery. It could be as simple as just stealing a translation patch and slapping it on a game then selling it, to people acquiring prototypes they don't legally own other than the physical media they're on and selling shit they have no right to (like the Nolan's and others making expensive numbered or not releases to widely fatten their wallets while acting like it's the good of the community at heart.)
A true honest to god repro would be what
www.pikointeractive.com does. Eleazar(Piko) goes to the original IP owners, or former owners to find the current owners. He then has meetings, conversations verbal/email, gets contracts done, and buys the IP outright or gets a limited licensing agreement to profit share or own X game for a specified time. All that stuff on his site is a smaller mix of amateur ROM projects but a good large amount are failed to hit the market games (companies fold, someone dies, console gets too old to bother.) He gets the rights to these with some agreement if not buying them, then releases the lost games or brings back the dead (like the Wisdom Tree stuff) as a co-profit sharing deal. Those are reproductions, they reproduce the original and legally so.