You are right about the mast. The cruiser had a tripod, and not a single pole like represented in the kit.
http://www.google.it/imgres?imgurl=http ... BA&dur=865There are several other "errors" coming out of the box, many of them very difficult to correct, so I guess is up to the modeller to chose how far to push the conversion (and never reach perfection anyway).
I started my Hobby Boss Pola yesterday after several months of research about this elusive ship and I came to the conclusion that, looking for fine details, many blueprints published from well known authors are wrong as well contributing to the general chaos.
The ship in the box seems to represent something from late 1940 and not 1941 as reported on the box, something I desume from the two (horrible) AA guns on the upper bridge. in 1941 my best guess is that those were removed and replaced by the single searchlight present in the model as well. you should chose between the AA and the searchlight
There "should" have been a pair of 120mm on the sides on right and left of the bridge superstructure but I have very few photos of them and not very clear.
Unfotunately the ship line is incorrect on the bow (too stright) and the stern (which was more rounded and with a different underwater line.
About the keel colour, I guess it's up to the modeller since there are no colour photo of it: since the ship was built at OTO Livorno and not in Trieste Arsenal, I'll paint mine in red, but there is no "right or wrong" on this matter.
BTW, I strongly suggest you to find a better anchor for the ship: thin one is way over dimensioned