The late Bill Mook told me that OALW was the private mark of a man (I believe now also deceased) named Ostborg who humped up fake Krag carbines, at least some of which were known as "Red Ryders" due to the particular color of stain that he used.

OALW stands for "Ostburg Armory and Locomotive Works" (he humped up toy trains, too) and is absolutely not any sort of official government marking.