Solaris 10 packages

can one install packages from different Solaris 10 subversion on a SPARC?
(if we don't have the install media for exact same Solaris10.)

Nope.

X86 and SPARC are different architectures

but I am thinking about SPARC versions only.

I got the install DVDs for both x86 and SPARC of Solaris10, but its probably slightly different version (month) than the one on server hard drive.

It depends what kind of package do you want to install. Also installing packages from lower version of the system than the current one might not be a good idea.