We recieve questions very similar to this often. The AAP page has a tremendous search feature in the top right. As an example, a quick search using the term "GPC + gift" instantaneously delivers two results that answer GPC and gift questions. Possibly helping you in a more timely fashion for your needs.
That said, the answer is "it depends". It depends on the purpose and context behind why the gift is being given, who is going to recieve it, etc., etc. Additionally, the service components often have rules that are more strict than Federal Government and DoD level rules (e.g. Army AFARS Appendix EE, USAF AFI 65-601, Volume 1) and/or provide more specific guidance.
The place to start is at the Defense Pricing & Contracting GPC site. Depending on the specific facts of your scenario, the FAQs page and the Policy Documents & Guides page should help point you in the right direction. After you've researched that, then find out if your service component has more guidance and or limiations.