That means the neck was made in the 13th week of 1973
On a Thursday, which means the neck was finished on March 29, 1973.
So you have what looks like a 1974+ body, a March '73 neck and a '72 neck plate. Even if it is a period-correct parts bass, that was a very good deal - and let's not forget that in essence, all Fenders are parts basses. Or it could have been assembled this way at the factory using 2 year old parts, I wouldn't rule that out, stranger things have happened at Fender in the 70's. You will know more after you strip the body and see if there are plugged tug bar screw holes on the treble side, like Dave wrote.
Did you look under the pickup halves? The stamps there should give more clues.
Congrats on the new bass!