My first bass was a Thunder 1a.
IMO you shouldn't underestimate Westone basses, they are well respected by those who owned them, mostly in the 80s.
It's unusual to see one for the price you quoted - it is difficult to gauge what a fair price is for Westone, though - you see them for £300 and for £1200 (one on ebay currently).
If you like it, buy it but you might want to try something "less vintage " to see how gear has changed in the last 40 years.