Odd Swiss 1906 Bern

[Lugers down under]

Hi Guys,
I need some help with a very nice Swiss 1906 Waffenfabrik Bern I purchased in an auction here in New Zealand a few days ago.
The gun is really in excellent condition with 95% blue and straw all over and a lovely barrel. The privatization date is 1945.
(I am sorry the photo is a little dark)






The gun has been fitted with a 1906/29 rear toggle section which is not numbered. The gun number is 21588 and is all matching numbers except the rear toggle section which however, does have an inspection stamp inside, E25 and a Swiss cross. The front of the toggle and breech are numbered 88 to the gun.
The gun also is fitted with a 1906/29 W+F magazine.






What is strange is that the rear toggle section is very similar to the 1906/29 W/F but it is not the same and has slight knurling on the outer sides while the "rims" if one can call them that are smooth like the later Swiss guns.
(see below)







There is some suggestion that it could be a transitional model but I do not think I could be that lucky. I think that it could be a rework.

I would be interested in any views you can share with me on this interesting gun.


Many thanks
Murray.