Yes, here's a couple of options for installing window grilles or mullions. I don't have any experience with either of these, but they're worth a look. Don't know how much you want to spend or how authentic you want them to look. The first one looks a little fake but is probably inexpensive. You can google window mullions for more options. If the windows are a brand name, you might try their website for removable grilles.

http://www.newpanes.com/howitworks.html
https://www.bigbluewindow.com/