The M45, and any dash version thereof is one of those cases where the model is so hard to find, especially in or near 98% condition, we're just happy enough to find one to buy! It certainly rates a premium over other mundane models, but not enough sold to establish a "going rate" by any means. And if there's a going rate but what you find is priced above that, do you really care all that much?
If you want it, you find the price is at least somewhat 'reasonable' for the condition, and you can afford it, then the price is right. Period. they aren't making any more, that's the bottom line.