I believe I posted the photo below a couple of years ago. I'm still intrigued. It's an appealing Jimmy Stewart on a repro. photo in blue felt tip that originates from the Kuflick collection. I found an earlier career album page in fountain pen that matches up to the photo signature style rather well.
I'm still slightly on the fence about the SP (but leaning toward authentic given the provenance). Finding this solid album page exemplar certainly makes for a great comparison. These signatures by him would been separated by decades.

