Mystery Long Branch #4!!

HELP!!! First off, though not an expert, I'm pretty clued in about Long Branch Lee Enfields, but this one has me stumped. I bought it from another firearms site, the pics looked good, and it's supposed to be a 1945 Mk.I* Long Branch. In the company of a very knowledgeable buddy, we tore it apart. Some parts are English (ie: the magazine, the micrometer rear sight, and the barrel). The foreward stock band is Savage. My buddy has dismissed it as a "parts" rifle and told me I've been screwed. I have a feeling he's been too abrupt in his evaluation, and there are some things about the rifle where I need some input from some of you astoundingly knowledgeable gurus.
More about the rifle; the receiver is a properly stamped, phosphated part correct to the period. The barrel is a 5 groove, blued, British proofed barrel with the proof marks near the muzzle end. On the knoxform is a large letter "I" and a *. Here's where it gets interesting. The serial numbers match on the bolt and receiver, but they don't conform to the normal Long Branch system (ie: number, capital L, and numbers). The stamp size conforms to the ones on my 1950 Long Branch, but on the left side of the wrist is the the following;
GERD (the "D"may be a badly struck 10)
L 0315

HELP!!! First off, though not an expert, I'm pretty clued in about Long Branch Lee Enfields, but this one has me stumped. I bought it from another firearms site, the pics looked good, and it's supposed to be a 1945 Mk.I* Long Branch. In the company of a very knowledgeable buddy, we tore it apart. Some parts are English (ie: the magazine, the micrometer rear sight, and the barrel). The foreward stock band is Savage. My buddy has dismissed it as a "parts" rifle and told me I've been screwed. I have a feeling he's been too abrupt in his evaluation, and there are some things about the rifle where I need some input from some of you astoundingly knowledgeable gurus.
More about the rifle; the receiver is a properly stamped, phosphated part correct to the period. The barrel is a 5 groove, blued, British proofed barrel with the proof marks near the muzzle end. On the knoxform is a large letter "I" and a star . Here's where it gets interesting. The serial numbers match on the bolt and receiver, but they don't conform to the normal Long Branch system (ie: number, capital L, and numbers). The stamp size conforms to the ones on my 1950 Long Branch, but on the left side of the wrist is the the following;
GERD (the "D"may be a badly struck 10)
L 0315
9
The same number is on the bolt in the correct location and the same size stamp. There is no indication the bolt was ground and re-numbered. On the lower stock are the letters "KB" just ahead of the magazine, and a little further on is "9X" (see pics). I have a feeling that this rifle may have an interesting story to tell, if anyone has the knowledge to decipher the clues.
Though I appreciate ideas and speculation, I really need solid facts and wisdom in helping me learn the tale of this old girl. Thank you in advance.
https://www.milsurps.com/images/impo...148dc01c-1.jpg
https://www.milsurps.com/images/impo...99a9446d-1.jpg

Have not seen any Long Branch rifles with anything close to such wrist markings! But otherwise, I'm with your friend: If you were wanting a "correct" 1945 Long Branch, then this isn't it. The barrel in particular is the deal breaker. (Other than the proof marks, what markings indicate that the barrel's British?