Wonderful find 4-screw. It amazes me how there are still "unused" specimens out there.
Your post got me thinking about the HP I just picked up last week. I guess I'm not very attentive but I did not know that '54 was year one. It just so happens that my "new" one might actually be about as old at it gets (S1133xx). I guess a letter is in order.
I just grabbed it because it was a good shooter and a pretty good deal (~450). After I got it home I noticed the unexpected bonus that it had the original stocks. (The pictures make it look more worn than it is.)