Curtis, yes that is it, what does the inside of the shell look like, here's where this could get interesting the original stainless steel prototypes where not stainless steel at all but ludalloy shells, your acro might have come from one of them?

I dont even know what the inside looks like. I know its missing the dampener but my buddy just tuned it and set it up for me. I should probably open it up and take some pics eh? I will post them soon. Anything I should be looking for particular?

Curtis take a pic of the entire interior shot, I'm looking for a welded seam not the standard acro interior.

Would the seam be running horizontal or vertical? I am trying to look through the bottom head first before taking it all apart. Will there be a very clear seam? I cant see anything vertically that stands out.

It would be a vertical seam. if you can't see one through the head then it's just a standard shell, it would look like the acro prototypes welded seam inside!

What is the deal with the hand scratched serial number though? Did they do that at the factory?

Yes it would of have been. as you'll learn about ludwig everytime you think you have them figured out, BAM something you've never seen before is being shown to you, like I just found out from my bud mortar he has a 14x14" clubdate floor tom with classic leg mounts not the standard clipper mount that normally comes stock on them and his is factoru no extra holes as the hole spacing for the two different mounts isn't the same, Franks drums shop would Oder blank ludwig shells and install what ever mount you wanted on them

My feeling is that it's as you suspected, a 1970 drum with a user-inscribed number.

Ok sorry to bring this up again but I bought another acrolite tonight w/case, stand, sticks, and practice pad, (early 70's badge just like my other) and low and behold a hand engraved serial number!

Coincidence?

Picking up another one tomorrow for $40 with a case! I cant help but buy these things when they are this cheap!