Differences between 1990, Delta 88 Royal and Brougham?

While doing some sanding work I came across a little square, the insert is long gone, but in the remaining glue I saw "ugham" so I guess mine is a Brougham? Whats the difference?

Sorry about all the posts lately, but you people are my best source of info.:grinyes:

Interior trim, some power components std, such as a 6 way seat, some minor exterior trim pieces.