Joe, if you see blistering at the chrome window reveals, you could remove the trim to examine what is going on. Protect your paint with blue painter's detail tape while you unclip the chrome trim retainers using the special molding tool. That would give you a chance to closely examine the channel to see if there is hidden rust. If it's minor you can scape and sand to bare steel and put a primer over it to arrest rusting.

Like fbody69 says, it won't rust if the rust is under oil.

If you store it indoors, it can go several years with nothing more showing up.

Here is a photo of my car and a close up photo of the upper right glass channel after the glass, sealant and chrome reveal were removed.

The rust didn't look bad at that corner until I remove the chrome to inspect things. That corner needs to be cut out and new metal welded in.