G'day Jim, Welcome.
That servicar would look good in anyones shed.
Roo.
Nice machine, Jim. Is B4 stamped on the R-H side of the steering head and just forward of the VIN boss? If so then I agree it indicates the frame was made in Feb 74.
Is there a manufacture date for the whole machine on the sticker on the front downtube?
Under the trans oil filler spout you may find casting number 121-41 followed by casting hallmark UF. Before the casting number, and just under the case body, you may find a casting date code.
Eric