Hi Murray, that's a part number for the engine block. The year code is a 2 digit number (eg. 92) and is stamped into the block under the inlet manifold. If in doubt post a couple of pics and we'll help you out.
Doesn't jump out at me Murray. Take a couple of pics, close up, of the area in question and one of the machine overall so we can help identify the age of it.
It may be a while before I get back to this. I had the roof blown off my shed in the wild weather we had on Wednesday and have had to put everything into temporary storage. Thanks for your help bigted, I'll post some pics up when I get back into it.