Note: I see no 163 stamping on this watch -
https://www.ebay.com/itm/184814420975
Comments submitted for S/N 5321099 may apply.

Note: That serial number of the Bunn Special is not a
163 type 1R. That watch comes from run 339 which
was a mixed run of type 3, 163 type 1R, and 163
type 1. The 163 1R had 163 stamped on the barrel
bridge next to the lower left barrel screw, the
163 type 1 had the 163 stamped vertically in the
center of the barrel bridge. The watch you have is
from the first 100 watches from run 339 and is
just a plane 23j type 3 (fairly common) and not a
type 163 1R ( really rare). Only watches with 163
on the barrel bridge are designated as grade 163.
It is a bit of a glitch on the on line data base,
but this information is from the most recent
studies of Bunn Specials by M. Chamelin page 223.
The range 5321001 to 5321100 should be type 3.
The watch was on ebay and seller had it as rare
type 1R.

Bob

No further details were submitted with the report.