Quick answer is no. But, I have a 2008 1900SR3 bought new with a Bimini and would gladly take some measurements for you this weekend. Not sure if maxum put same biminis on 1800 as 1900 but good chance it's close. Just let me know exactly what measurements you'd like. Also I am not sure Bimini is an OEM item or dealer installed item. All I know is mine was on the boat when I bought it.
Same admiral since 1973
New Boat 8/13/11: Chaparral 206SSI with 5.0 VP GXI SX
Prior Boat: 2008 Maxum 1900SR3, 4.3L V6 190HP, Alpha 1 (great boat)
2010 Ford 150 XLT Super Crew 5.4L V-8, tow package
2008 Infiniti G-35