Yes I agree. Ackley apparently did a lot of rebarreling work which would have of course been marked. The credibility for me comes from the position of the Ackley stamp.. at top of the barrel several inches in front of the receiver where a manufacturer's stamp might be, rather than right next to the caliber marking. Also the aforementioned unmarked receiver (above the wood) such as a manufacturer might buy, and of course the custom made recoil pad with his company name. Taken all together I believe these things make a case for a completely Ackley - made rifle as opposed to a simple rebarrel. I would be interested to hear from those more knowledgeable than I of course.
The rifle came from an estate and afaik no documentation is available.