I don't know if you folks are still interested after several months... but I just got a similar mobo hand-me-down, and searching E139761 didn't get me anywhere. But the Intel support site recognized a number from the solder (back) side of the board.

Mine is "Intel Type: SE440BX2", right next to the FCC logo, directly opposite the processor's heatsink. Result = PDF product spec (http://www.intel.com/support/motherb...cs-013640.htm).

Hopefully, using your Intel Type # will get the info you're after.

PS- I didn't look up the FSB on a P3-450, but the max FSB on this mobo is 100 MHz.