I will be going on 60 years old. I'm not a fan of deals where the seller won't state a price. Point out that you don't want to unknowingly insult them with a lower than expected offer. If they've listed the item they should have an idea what they would be happy with and more importantly what the market will bear. You may give a higher price than the seller was expecting. Remember, you are the one who is taking on the cost and burden of transporting and fixing the unit. If in the future it no longer fits your lifestyle, you will be faced with these issues from a potential buyer. I've been fortunate not to have to replace more expensive and hard to find parts like transformers but there is always that possibility.
It does look like they, or you, have done some sleuthing on the components of the unit. If they are expecting close to Ebay sold prices for the components, then they should be prepared to go the Ebay route(with all its headaches) to sell them. I did see some completed sales for the amp. One was $50 though this seems to be an outlier with a very low BIN price. Unless rare and highly sought after, consoles usually sell for far less than the sum of their parts.
Unless this particular model has sentimental value there will be others. It may take some time but I enjoy the journey. Let us know how you fare and good luck!
Mark