@CoachMac Yes, keep the cable. As far as the Sony PVMs, just be careful buying one on eBay. They are heavy and if they aren't packed right, it's not making it to you in one piece. There are state public auctions that go on that usually have these monitors that go for cheap. It's all done online, you bid like eBay and if you win you go pick it up.
https://www.ebay.com/itm/Sony-BVM-1315-Monitor-/252883026915 - I found this one on eBay. The BVM monitors are the next step up from PVM. This one is only 13" and it's located in Sparks, NV. No speakers though, you'd have to use some cheap computer speakers.
You can use this adapter to try it out with just the Genesis AV cables. - https://www.amazon.com/Sienoc-Male-Female-Adapter-Connector/dp/B00KX17NGU/ref=pd_lpo_vtph_23_bs_t_1?_encoding=UTF8&psc=1&refRID=YVBQ4Y5AHEQRRG6G0BWN . See if he would let you test it out.
If you like it, I'd offer the guy $150 and see if he takes it. He wouldn't have to pay eBay fees if he sold it to you locally. That's not a bad deal for that monitor.
You will need a SCART to BNC cable to use your RGB cable for any of these monitors. https://www.ebay.com/i/202264834157?chn=ps&dispItem=1