For its age, that pin looks to be in great shape. I'm assuming the original owner placed the cardboard over the plastics to protect them from UV while in storage. Have you had a chance to remove them yet? Based on the condition of the playfield, I would expect the plastics to be in good shape as well.
For $150, it's a good deal. A working pin for the price, and in that condition is pretty uncommon.
But there are a couple of possible negatives. The EM pins can be a real bear to maintain. As the old adage goes "More moving parts means more things that can break." Logic boards don't fail nearly as often as relays do.
The other, and perhaps the most important one, is that the game itself doesn't really look especially entertaining as pins go. The playfield is pretty sparse, with a limited number of target types. You might find that you play the heck out of it for few days and generally taper off until you finally curse it for taking up the space, assuming space is any concern for you.
The only reason I say this is I bought a Williams High-Speed last year. I spent a lot of time fixing it up, painting bad areas on the cabinet and playfield, put all new rubber on it, etc. I played it hard for a couple of weeks, then went to a game every couple of days, and now, I think it's been over 2 weeks since I last fired it up and before that it was a month. I wouldn't want to get rid of it because it's still a fun game, but it takes up a good chunk of a room for something that doesn't get used very often. If the game wasn't still enjoyable, it would be gone.
As for the lock, I wouldn't drill it unless I had an identical replacement in hand. Considering the condition and the age, it might have some value to a collector somewhere. The more original it is, the more value it will retain. If the above is of any concern to you, at least get a picture of the lock before you destroy it so you can make sure the replacement is the same.
RandyT