Is the CT3309352 Crucial memory the same as CT2K4G3S1067M?
Here is the result of my conversation with Crucial. Given their quality and reliability as manufacturer and supplier, I personally am tempted to spend a little more and source the upgrade kit directly from them. If any problems then should be easy to have it fixed.

[Mark:  Hi Can you tell me if CT3309352 - Crucial and CT2K4G3S1067M are the same part numbers for a Crucial upgrade 8GB kit for the MacBook Pro mid 2009 13" or are these two similar but different units produced by Crucial?

Crucial Agent :  When you order by advanced search or by motherboard/system information online, you are shown the “external” part number CT3309352. The part number that you see on your module is the actual module base part number CT2K4G3S1067M. If you order by advanced search or motherboard/system information, the external part number is included in the packing list with your memory module. The modules are exactly the same. They are the same part. And will work in your MacBook Pro mid 2009 13".

Mark:  Thank you. So you are saying depending on the method of search, you will get two different numbers but they are a reference to the identical unit that will be compatible, with above MacBook Pro?

Crucial Agent:  For some systems yes. Some times you can look up just by the part number CT2K4G3S1067M and put it in to find it, but it is not always show any results when doing this. Normally only the servers show the actual part number. But this one is listed as compatible for your system and will work.]

So there you go this should help.
Cheers
Mark