LS puts it as a concert sized L series guitar (not an LL). The X denotes onboard electronics. Given the tuners, I assume the instrument to be from the 80s or earlier. It looks like a Stika top and mahogany back and sides. Beyond that, I can't help much but to say it's a nice find, especially if you got it under $500.
https://yamahaguitars.nl/facts-figures/the-l-series/
Based on the article linked above, it seems to be from 1978 - 1984, all solid woods, and handmade.