I think the only sure way, if you don't have a manual for the motherboard, is to try it. Some boards do need paired sets to work.
I went to one shop to buy some new RAM for an older computer. They tried to tell me that older boards can NEVER work with newer RAM. I disagreed with them (previous experience of building from scratch and upgrading told me that wasn't the case). They then told me I must buy a new motherboard and CPU as well as RAM, so I walked out.
I went to another shop I knew just down the road and they agreed to sell me RAM on sale or return (very good of them). It worked just fine.
The first shop went bust a few weeks later - I wonder why?