It seems none of these were very much distibuted but the DR-M4 was available in black or silver just the same. Its little brothers (DR-M3, DR-M2) were only produced in silver.
Having seen all three versions, I can safely say that the DR-M3 had the best balance between the technoid black and the tackiness of silvery plastic. It should be noted that the DR-M2 was released in 2 versions, the better looking of which is shown here ; the other one had a blue <play> touchpad and no grey extension to the left.

Depending on market, wood-sides were an option for all.

Denon DR-M4
(1983 - 1984)

Flat surfaces and Hi-Tech functions. I've owned one for about 10 years and it was a great sounding deck. Like Sony with the earlier TC-FX1010 (which I now own as well), or Pioneer in '81, Denon went all out on design&technology with the M series. Seemingly the audience wasn't yet ready for that kind of looks for the next lineup (DR-M44/44HX) sported quite conventional controls, knobs and panel layout - modernism is a fleeting thought.

This deck was filled with all the niceties that had started to appear on consumer decks: C Dolby, Quartz Lock, Direct Drive Closed Loop Capstans, Computer Servo Mechanism, digital counter, remote-control (wired), separate power supplies for the motors and audio stages etc. However, it was made of plastic for the most part ... The big thing, though, was the Computer Tuning System: it could adapt the deck's bias & eq for each individual tape inserted, with a capacity of 100.000 possibilities! The lower DR-M3 featured the same CTS but none of the capstans/motors/Quartz features ; the DR-M2 was a 3 without the CTS but a 3Head design just the same. The DR-M1 finally gives up with only 2 heads.

My DR-M4 recently celebrated its 20th birthday... it had (very well) recorded many a cassette but it is just too bad the chassis wasn't on par with the mechanism.