All the above is fair comment, but note that I used the word "gamble"! It is obvious that one cannot be sure that this movement, or indeed any movement, is in good condition without pictures. I have gambled on about six watches with no movement photos over the years and every one has turned out well. Of course that does not mean every gamble will work out ok, or it would not be a "gamble" at all.
When a watch is listed on ebay with no movement photo, some people will not bid on principle. This means a potential bargain for somebody else. Below is my beloved Seamaster De Ville, my first quality vintage watch, won on ebay in 2012 for £275 complete with BOR with photos of the exterior only. After servicing, this watch continues to keep time below 5 seconds per day. So a risk can pay off.
Looking at the dirt on the back of the watch shown above, I do not think it has been opened recently and so I doubt the seller knows anything about the condition of the movement. The seller also says it is in working order so the movement can't be that bad. OP has enough information here to decide whether this is a risk worth taking.
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