MK2 MOD1 SPL barrel meaning??

[Ed42]

Just trying to find out more about my new rifle. The barrel is marked SA 11010457 SPL 9 65. MD50 followed by the proof with the stars on it.
Also 7.62MM and a capital P for Proof and a capital M for magnetic particle testing. The part I’m interested in is the SPL!!!
In reading Canfield on page 585, he notes that the USMC did fabricate a limited number of 7.62 Garand match rifles. He sets out some details… one of which is “The 7.62 mm barrel was marked SA 11010467 SPL 9-65.” I haven’t taken it apart yet to see if some of the other things like polishing the op rod and if the last four digits of the serial number is stamped inside the barrel channel, etc! I would sincerely appreciate any thoughts on this especially the SPL. He showed a detailed picture of two standard service grade MK2 MOD 1 rifles on p. 582 of his book and both read SA then the drawing number then the date then MD and a number. Both examples lacked SPL. Another pic below those did have SPL in the sequence but he didn’t say what it meant. Thanks any thoughts on this.

[MAC702]

"SA 11010457 5 85 BU18", and the other stuff. No "SPL" for me. I'll look around at some others later.

I've a large print "H&R 7.62 NATO" underneath, even though there is also a small print "7.62 MM" at the chamber.

[Ed42]

I don’t have 7.62mm on the top line along side SA and the drawing number etc. 7.62 MM is somewhat larger and below the other printing. 7.62MM is not highlighted with white. THANKS FOR REPLYING!!

[LavaTech]

Bill Ricca could find no specific reference of any sort for the SPL markings of MOD 1 barrels, but did find that SA 11010457 SPL 9 65 stamped barrels were originally produced using a .30 cal gas port, later drilled out in use or post production.
Basically, a whole bunch of not a thing known about the SPL marking, AFAIK.

[Ed42]

Thanks everyone!!