You can run a "strings" over the binary and grep for "3.4" to find the
following banners.

This is the version we're shipping on ftp.arm.slackware.com:
U-Boot 1.1.4 (Oct 27 2009 - 21:57:24) Marvell version: 3.4.19:
http://openrd.googlegroups.com/attach/82f086b82c44e412/u-boot-3.4.19-openrd.zip?part=2

The link to an older version if you want this for any reason:
U-Boot 1.1.4 (Apr 22 2009 - 20:18:28) Marvell version: 3.4.16:
http://code.google.com/p/openrd/downloads/detail?name=openrd_uboot.zip

Other downloads can be found at:
 http://code.google.com/p/openrd/downloads/list