Maico 250 dirt bike 1977-1979

Maico 250. Purchased used in 1980 and rode it off and on until 1995. Moved to the suburbs and stored bike inside for last 20 years. Worked well when stored. External rust (see Pics). Engine turns over smoothly but I have not started it. Unsure of year. I always thought it was a 77 but from pics I can not tell. The info tag (see pics) is hard to read. If anyone can ID year / model from pics I would appreciate a comment. Mileage reads 1645 but I do not recall if speedometer was working back then.