I have an ignorant answer for you... I don't know. The best thing to do is test it. Do you have any wood left over from construction? If so, put a couple coats of the original finish on it, and then try the Permalyn. If you don't have any original scraps, look under the barrel of the gun. Is it oiled with the original finish? If so, test the Permalyn there, where it will not normally be seen. And for even more ignorance, I have no idea what tip Curtis finish is.
I am sure others here will chime in and give better direction. Good luck with it, Bowkill.
Matt