In order for me to properly assess what you have I will need to know the size and see images of the front, back (do not remove from frame) and a clear, in-focus close-up of the signature. You can do this by using the AddFiles feature on your screen.
If you had already attached images to your initial posting, they are not showing for me here on my end.
I do specialize in fine art as well as my other specialties. I am a published author on art and I am also a watercolor artist. It is required for us to ask for photos of art in order to give an accurate answer.
I will opt-out and allow another expert to answer for you.
You can email your images to***@******.*** and write “For Rarewares/Antiques” in the subject line of the email.
Photos sent by email do not arrive to me directly nor instantly, they get forwarded to me by administrators, so thank you in advance for some patience when sending this way.