You could buy the window switch and use it instead.
Here's the difference and the changes you'll make...
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The red arrow points at the main difference. On the lock switch, that post is an angle shape. (Looks square in the pic. It is only an angle.
On the window switch, that is a solid round post.
What you do is cut the round post off of the window switch. (Simplest thing to do about this post.) Just be careful, when you plug the window switch in where the door lock switch was... That you get the post in the same place.
If you really really want the square look of the lock switch cover/bezel/whateveryoucallit...
The two green lines point to tabs on the side of the switch. There are two identical tabs on the other side.
I have two old window switches and I have opened them up. The little contact points corrode away.
As you mention above I wondered 'if' I could swap a window switch for a door lock. My concern was, the door lock switch gets a hot wire to it to lock/unlock the doors with the key off. The window switches need the key 'on' or in the acessories position to operate.
I'll certainly look into your suggestion
With these switches, if you are very careful, you can lift those tabs, and lift that cover off of there.
Do the same with the window switch.
Now put the door switch cover onto the new window switch instead.
That, along with the cut off post, will allow you to use the window switch in place of the lock switch, and still have it look factory.
The switches are absolutely identical, other than these two differences. There is absolutely no problem using one to replace the other.