Looking at the photos. Great revolver! The box end tells a lot.
http://smith-wessonforum.com/attachment.php?attachmentid=527231&d=1628970898
"Modified for IDPA" says a lot. The previous owner wanted to be competitive. Aside from the mentioned modifications, I would bet there was an action job done.
"…Cut to 4"…". Tells us it probably started as a 5" barrel.
"Hard chromed". Which was done for competition. Why would they lie?
"Now 45 ACP". This tells me it started as a 45 long Colt and was machined to accept full moon clips. The chambers are numbered and appear chamfered. Chamfering is a good idea. Not sure about numbering.
Does a long Colt round fit?
Kevin