I looked to see if I could find something more definitive in a diagram or literature. I haven't been too successful.
Some of these models literally just fell out when you turned the assembly upside down and tap them.
There was a model that took an allen wrench in the middle and would screw out. Does yours look anything like that? I'm sorry I can't remember exactly how this model's orifices are replaced.
Also, if another set of orfices were needed they would have been attached to the range in the back usually by the regulator. They usually are found many years later still there. They can be in a small envelope, plastic bag and sometimes they were attach to piece of sheet metal and screwed to the cabinet.
I checked the regulator and there seems to have been only one. That means you would adjust regulator (down) after you do the orifice replacement.
I could not find any LP kits for that model (most parts are no longer available).
I just realized that this is a 20" model (apartment size), right. So, almost all of these were made by Peerless (at least for the last 15 years or more). If we get jammed we may be able to go there for replacement orifices. I will see if I have a Peerless to look at today at the shop and that may also trigger a memory on how to remove the orifice.
I'll get back to you either later today or tonight on what I find.