No, the 1.0.94 version on www.blackberry.com/messenger
will not work on the Pearl or any other 4.2 devices. On 4.2 devices the BBMessenger is loaded with the OS. The only way to get BBMessenger back on 4.2 devices is to load it using the Desktop Manager and the OS installation package from the PC. Only BBMessenger v 4.2.x will work on OS 4.2 devices.