Those links appear to be broken. Luckily, I have a hardcopy of the BS VIN coding.
175s have a model code of 16, so your VIN should be 16-X-NNNNN, where X is the month code of manufacture and NNNNN is the build number.
The month codes are letters, A-Z with the exception of X and Y. A to L signify the months January to December in an even year, while M to Z signify the months January to December in an odd year (W = November in an odd year, Z = December in an odd year, X and Y are not used). In practice, the year of manufacture has to be inferred from the build number.
Some examples:
16 A 03736 = January 1966
16 M 22448 = January 1967
16 O 27401 = March 1967
16 R 31816 = June 1967
Bikes built after 1970 will have a compliance plate on the headstock with the date of manufacture on it.
And finally, the engine and frame numbers (with a TA1 prefix denoting the 175) will not be the same, but should be within a couple of hundred digits of each other. If they're further apart than this, it means the bike has had an engine change at some point.
Wish I could take credit for the above, but I'm just summarising from the (uncredited) info I have...