The first pic is of a good example with the CR2016 lithium battery installed. Notice the greasy fingerprints. Wash yer hands and wear gloves ya filthy animal! Extra grime from dirty hands and a dirty work area is not very professional and makes extra work. Delicate electronics and your mother agree.

If you are extremely lucky the watch is in good shape and does not have a lot of foreign garbage inside. If the module inside is corroded or has signs of corrosion a battery replacement is not recommended until the module has been thoroughly inspected. I will be doing more guides for this watch.