I don't know how a date of Nov. 22, 1940 (as I read it) works out to mid September, but I would advise you to remove the barrel before bluing.  Unless, of course, you are only "touching up" some worn spots.

If you've never done it before (or for those who haven't) the thing to do is put a spacer in the receiver to fill the space where the breechblock goes, put the barrel in a barrel vise with properly fitting jaws/inserts, then turn the receiver off with a properly fitting and padded receiver wrench.  You can make or jerry-rig any or all of the above mentioned tools, but they are all needed to do the job right and not damage the receiver or barrel.  BTW, the threads will generally yield better to a sharp wrap or tap rather than trying to gradually apply more force a little at a time until they give.  Oh yeah, don't forget to remove the extractor before you start... leaving it in is definitely a Bad Thing!! 

Froggie

PS  Why remove the barrel before bluing?  If the salts get into the threads and are not neutralized, nasty things will occur in there!!