If that was the case, STONES.ASM would assemble to STONES.LIB and CLEAR.LIB at the same time. The assembler they used must use this keyword differently than MASM. The data in this ASM file isn't nearly enough to represent the rich graphics of Pinball Fantasies.
Skimming it, it has lots of data (or, possibly, bytecode that gets interpreted) and has a section called “animations” (starting at line 2259)