Thanks everybody for all of the information!

Putting all of the facts together it makes sense the previouse owner had it converted to .44 special.

Two things I am curiouse about,

If S&W did the conversion work,
Would a factory letter give any details about the conversion,
Or just tell how the gun left the factory originally?

Also,

If it did start out life as a .45 and the conversion was done by S&W in 1967,
Would the previouse owner have had the option of converting to .44 Magnum instead of .44 Special?
Or are Non Magnum frames not up to the task of handling Magnum pressures?