need help on WW1 motor info OT.

ok, heres the skinny, been working a deal for a few months, on a German WW1, 77MM light mortor, when i thought the deal was sour, he called me the other day needing some money,
heres the question, i know that breach loading WW2 Art, has to be modified by welding, bore plug ect, to make it legal to have, and make it art deco.
this is a muzzle loading cannon type deal, and from what iv read, its not a distructive divice. as long as it loads from the muzzle..yes, this one is live, and not modified {yet}
can i take delivery of this the way it is, or does it need to be modified as art deco? this peice was made prior to 1915. and is in rough shape.
i need facts, and not opinions on this , by someone who collects heavy ord.
this is a big money deal, and i dont want to loose it, or worse get arrested and loose my life savings, among other things..
iv delt with demilled big guns in the past with eas, and turned down live ones, that i know were fishy,
this one isnt fishy, and would look great in my back yard. lol.
i had a couple 37MM anti tank guns for a while..and a 75MM howitser.
alot of fun to enjoy, and they sell easy. big money collectors on heavy guns.

this is a file picture of a display gun, i noticed this one is live as well, and not demilled,
every one iv found for display, is live..

I am curious about this also.Mortars seem to have several different rulings depending on the ignition/launching method.One ruling states-German Minenwerfers,old and new models,mfd.prior to 1919,utilizing radial,straight pull friction primer ignition system were removed from NFA and GCA and classified as antiques.Another ruling on German Minenwerfers-having fixed firing pins,spring or hammer actuated striker,any cal.,any model,mfd.prior to 1919 is classified as a C&R but subject to the NFA.I have looked at some of these at VFW and AL posts and some were de-watted and some not.What is the correct answer?