The rear sight ladder has a P and below it a CR40 (C? can't tell last digit). The slider is marked with a P and a CR318. The buttstock has an L just forward of the buttplate tang.The Long Branch Singer sights had a relatively short life. Too expensive and time consuming to manufacture but if you can find one today you're looking at $100.+ for one with the "LB" stamp. I can't see the letter at the top on yours in the pic, but if it's "F" it's Fazakerly, or "B" I believe to be BSA. Also on the Long Branch Singer sights had a smaller peep aperture than the British ones. I believe your '44 should have Mk.II or III sliding sight. IIRC, the unpopular "300-600" flip sight had been replaced by that point. You have a black walnut buttstock and birch fore end wood. The Canadian wood in '44 would probably have either the "LB" or C-Broad Arrow stamp.