Yep, all Sunlines from about 1986-2007 had a 5 on 4.5 lug pattern, meaning 5 lugs on a 4.5" bolt circle center line. May have been earlier too, but I'm not sure what was hiding behind those hubcaps.
1986-2003 I believe had some 14x5.5 rims available with this bolt pattern, used on smaller trailers. The lug pattern is the same between them though, and they're rated for ST205/75/R14 load range C tires. Some really small trailers up through 1986 used some smaller 13" wheels, but I'm not sure of the specs on those.
1986-2003 generally 25' and larger trailers used a 15x5.5 rim, 5 on 4.5 bolt pattern, rated for a ST205/75/R15 load range C tire.
All non-slide trailers from 2003-2007, as well as Transport trailers from 2005-2007, used the 15x5.5" rim above, regardless of trailer length.
All high-profile slide trailers 1996-2007 used 15x6" rims with a 6 on 5.5 bolt pattern, rated for ST225/75/R15 load range D tires.
2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR