NVT 125 Rambler

[Hyatt]

I have recently purchased a Rambler, I know this not actually a BSA, but it became the BSA Tracker. My understanding is that these were only produced for a couple of years (76-78), I am wondering if anyone would know how many were actually built and sold? In nearly 50 years of motorcycle ownership I've only ever seen about four others, apart from mine. I would also like where I could get spares from.
Thanks
Tony