Apparently the weight was 133.7 kg according to the following Russian site: -
http://ww1.milua.org/TUF.htm
I think I'm safe in assuming that weight is for the gun as well as the carriage it was mounted on... so, not much help really...
According to this page, muzzle velocity was approx 805m/s and cyclic rate was 300rpm: -
https://it.wikipedia.org/wiki/MG_18_TuF
According to one of my books, there are two examples in museums, the German military museum in Koblenz and another in an un-named museum somewhere in Russia.
(Book: pg 185, second last paragraph,
Machine Gun: The Development of the Machine Gun from the Nineteenth Century to the Present Day, Maxim Popenker and Anthony G. Williams ISBN 978-1-84797-030-5).
Your best chance might be contacting the German museum which I believe is the Defence Technology Museum (Die Wehrtechnische Studiensammlung).
This website has contact details for the museum: -
https://www.tripadvisor.com.au/Attra...alatinate.html