OK, it's definitely a model 610 from either 1983 or 1984.

The way to positively identify the year would be to have the original paint colour, but that's long gone, unless you want to look for overspray remnants on the fork steerer and in the bottom bracket.

Alternatively, we can go through the complete list of components and see what is the best match, given that we already know some have been changed out. One thing that may help is the freewheel. The 1983 model was 5 speed, while the 1984 was 6 speed. Please note that the presence of a 6 speed is not a postive identification for 1984. There is always the possibility that it was swapped out at the same time as the derailleur. However, if it 6 speed and you have to spread the stays to get the wheel in place, then you know it's a retro-fit and that you have a 1983 model. A 6 speed with a good fit in the stays, indicates it is probably 1984, but there is still the possibility that it's a retro-fit and the original owner went through the exercise of having the stays cold set to the correct spacing.

Maybe knowing the exact year is not important to year. However, if it is I will go through the process with you. Reagardless, what you have is a good mid-range touring model. The main frame is Miyata double butted CrMo with hi-tensile forks and stays. Original cost was about $375 US.