Unusual VIN on 60 TR3A

[EPaul21988@aol.com]

List;
 I just acquired TS 71101L.  Immediately above the usual ID plate there was
an aluminium plate of the same size, stamped convex not concave with the
following:
TRIUMPH STC-62

This  also precedes the usual VIN on the California title which came with the
car, so the VIN appears as: TRIUMPH STC-62TS71101L on the title.

Any ideas where this came from or what it means?

Bob Paul
Corrales NM