If DC means the Nation's Capital if you PM me nicely we might be able to arrange a meeting and you could play my B50.
I had a nice response typed out but then I had to get out of my chair. As long as I was up I went to the library and about half of what I had said was wrong according to Beesly's book. So I will paraphrase that and maybe someone will have better information.
Hans and Beesly both agree that the B50 was introduced in 1975 and still in production in 1977. Beesley says production ended in 1987 which happens to be when B30s were introduced so I guess "the B30 replaced the B50" is true. The specs are almost identical according to Beesley. The B50 has an arched back. The B30 is 3/8" deeper. The scale lengths are different but I think that is a marketing inconsistency. Sometimes Guild published a 30 1/2" scale and other times they rounded and claimed a 31" scale. Beesley says both had the split bridge but I think at one point the B30 dropped the split bridge and reverted to one piece bridge. (Intonation is potentially better with a split bridge). A transducer was a factory option for both, according to Beesley, so the question about acoustic only is based on an incorrect assumption. Beesley says both were offered with fretless as an option.
Both Moust and Beesley fail to mention a fretless Starfire bass as a factory option.
If you have just found out about the B50/30 let me say that the B50 does one thing very well and that is project in an acoustic only setting. If you are going to run it through a mike, or amplify it or just noodle around because learning bass might be cool, the ergonomics are awkward and there is probably a better bass (even a better Guild) for your purpose.