Found the $4500 brush in the converted .map file. I had already looked at it, but didn't test anything, since I don't know how to recompile a .map file
Code:
( 4544 6272 2048 ) ( -2240 6272 2048 ) ( -2240 -1024 2048 ) sky_toujane 128 128 0 0 0 0 lightmap_gray 16384 16384 0 0 0 0
( -2240 -1024 2112 ) ( -2240 6272 2112 ) ( 4544 6272 2112 ) sky_toujane 128 128 0 0 0 0 lightmap_gray 16384 16384 0 0 0 0
( -2240 -1024 2112 ) ( 4544 -1024 2112 ) ( 4544 -1024 2048 ) sky_toujane 128 128 0 0 0 0 lightmap_gray 16384 16384 0 0 0 0
( 4544 -1024 2112 ) ( 4544 6272 2112 ) ( 4544 6272 2048 ) sky_toujane 128 128 0 0 0 0 lightmap_gray 16384 16384 0 0 0 0
( 4544 6272 2112 ) ( -2240 6272 2112 ) ( -2240 6272 2048 ) sky_toujane 128 128 0 0 0 0 lightmap_gray 16384 16384 0 0 0 0
( -2240 6272 2112 ) ( -2240 -1024 2112 ) ( -2240 -1024 2048 ) sky_toujane 128 128 0 0 0 0 lightmap_gray 16384 16384 0 0 0 0