Your serial number falls early in the R30001-R99999 series, 1970 to 1973. It was probably built in 1970.

If it were after 1983 as diamondback68 states it would have a 3 letter prefix, not one.

I see that as I type this ken158 has also made this correction. SCSW & SCSW3 shor the R serials were only models 60 and 651.Obviously at least one Model 33 had an "R" SN!!