Evansste,   I am not certain as to why they would need a svc tag at all. Now in the past we had servers with mid life motherboard changes that would affect dimms supported, but not with the R910. The only basis i can see them asking for is to define how many memory risers are installed to know how many dimms you can upgrade.    As far as the svc tag goes, it wouldn't change the supported dimms for the server even if you give another R910 svc tag.    Let me know if this helps.    
I own a Dell PowerEdge R910 server.  I want to upgrade my memory by using 1x32GB memory modules.  I've noticed that HP makes cheaper memory modules.  So I've been trying to find out whether or not they'll be compatible with my server. When asking a person, who is selling this memory, whether or not it will be compatible with my PowerEdge server, they asked that I provide my service tag number.  I don't currently have access to my server, so I can't look at the number.  I've been able to get the service tag number from another PowerEdge R910 server.  If I provide that service tag number, will I be able to trust that it will be good enough for this seller to make their assessment of compatibility? I never figured that memory compatibility would rely on a service tag number.  I always figured that the Dell server specs information would be sufficient.  If I provide this service tag number, from another PowerEdge R910, is there any chance that this memory may not be compatible with my PowerEdge R910, which will have a different service tag number? Thanks for your time.  I look forward to any information that anyone may be willing to provide.
Do I Need to Know My Service Tag Number In Order to Upgrade Memory?