I just bought my first MB fountain pen. I decided for a used 146. The seller knew about pens and said it was from early 90's. The pen was shipped with some ink (unknown brand), has a monotone nib 14K, what seems a plastic feed, brass piston threads, Germany in the clip ring, no serial number and some accessories. The ink window confuses me because it is not clear, it has black stripes but a bluish glow.
I will like your opinion as to the overall state of the pen and if there is anything I missed (Is it real?) (I checked several posts here to compare). Also, any recommendations as to cleaning or caring for the piston and nib.