Macintosh Type 1 fonts have a type of 'true' instead of 0x00010000. There is a patch for ghostscript 5.50 at http://www.cs.wisc.edu/~ghost/aladdin/relnotes/gs550/990120a.txt It's pretty short. Surely it wouldn't be hard to add it to 5.10.
It'll be fixed in 6.2 (we'll be including 5.50 with fixes as soon as it gets GPLed, which should be in 2 weeks or so).