My new mobo supports dual channel so I bought two sticks of 1 gig each of the same part number, as I know only identical ram will work in dual channel. They were not packaged together as dual channel twins but are from a large and reputable mfg. Although the sticks have the same part number on the packaging the modules on one stick are shorter than on the other. and I can find no numbers on either that are in common except "1 G." Is this something to worry about?
Thanks

If they are from the same manufacturer and will both fit the memory slots, I wouldn't worry.
The worst that could happen is that they won't operate in dual channel mode.
If they won't, contact the manufacturer and tell them they had a packaging error and you need to exchange for two matching sticks.