Don't 650 and 600 use the exact same firmware anyway? Afaik, the units are physically identical except 650 has a camera [and 650t has a bigger flash drive than 600/650].
I'm sure that all Montana use Unicode maps anyway. Look for 'UnicodeMaps' in it's GraminDevice.xml to be sure.
EDIT: Just looked in v5.60 firmware [the only one i have] and there's references to U N I C O D E [Searched 75 2E 6E 2E 69 2E 63 2E 6F 2E 64 2E 65 in hex, 2E wildcard].