This is a used vent. It will fit models 228F through 228J. This vent has some paint chipping and one small dent on the outer rim (see photos).
This vent will fit only the 228F model with a smaller burner frame made up to about 1971. After that, the F model used a different burner frame that included 4 bumps where the uprights are fastened. The mounting location is only 5-1/8" on this vent. This vent will not fit on late model F with the wide burner frame or models G, H, J or K either. Please make sure the top of your 228 frame looks like the photo below.
If the top of your burner frame has bumps, this vent will not fit. See photo below for an example.