Relic lover, as far as I know there is only one variety of this design, eagle and shield with star. Relic lover, I have the picture of it in front of me, and I'll send it to you privately if you pm my address. (reluctant to post this specific picture as the copyright laws are very srtrict regarding it) Perhaps in the meantime, as you now know what it is, you can get a "no copyright problem" picture off the web.
Anyway, I found a little information as to why it may have been cut down! (remember, your's measured 4 1/4 by 5 3/4 originally)
"On May 19, 1814, the Commisary General of Purchases wrote Lt. Col. J. R. Fenwick, second -in-command oflight artillery. asking his opinion of a new design and stating flatly, "The present light artillery plate is too large by one half"
Your's is the plate he was refering to. Your's is possibly a unique example of a cut down design possibly remounted on a smaller plate. At any rate, your's is extremely rare.