Probably not.
There are old-style ashtray bridges with three and with six saddles, and those tend to be interchangeable. They are not interchangeable with the more modern six-saddle bridges without the ashtray edges (USA Standard), however. The ashtray bridges are a four-screw model, with the screw holes between the string holes and the pickup rout. The modern bridge is generally a three-screw affair, with the string holes between the screw holes and the pickup rout.
Hope this helps -
Bagman