What I can say from every Parker (that I recall) that I have actually worked on, or taken apart for parts, the shields has been held in with brads. Same goes for Ovals on higher grades too. Like I said, I have seen stocks that have shields without brads, just never taken the shields out.

I do have an DH stock sitting around that has an oval with no brads though.

This does raise a very interesting question about Parkers applications of the metal mounting plates.

Seems to me that I remember a thread somewhere that talked about shields on English guns having a post on the back of them, and a hole in the stock which was filled with shellac and then the shield and pin were inserted. If you ever wanted to remove the shield, you heated the shield and the shellac melted, allowing removal

That is how galazans shields are. They have a single pin attached to be center back side of them.

This may or may not be of any interest, but I did a quick inventory of everything that I have here in the shop for guns and stocks to see how the shields / ovals are mounted.

I won't list the serial numbers and details on everything, but I have 19 examples here and 4 of them have metal mounted with no brads. The other 15 are mounted with brads. Of the 4 not mounted with brads 2 of them are shields and 2 of them are DH ovals.

The year range on the ones with brads are from 1891 - 1930 and the range of dates on the ones without brads is as early as 1903 and as late as 1938.

Of course, all the ones I have on hand that mount with no brads I have not removed and have no intention of doing so. So I am not sure how they mount.