If its legal to own a fawn hide in your state, its legal for you to possess that hide/bag anywhere.
Remember, the Burden of Proof is ON the Authorities attempting to charge you with an offense. No prosecutor is going to pursue charges against you if the police have absolutely NO evidence that the hide/bag was acquired by you in That State's jurisdiction, where it may be a crime to kill such animals.
This question is raised all the time. Typically, if a cop is so arrogant as to actually seize your property and charge you with a crime, A Motion to dismiss, with your affidavit stating where the hide/bag, etc. was acquired, that the State where you acquired it allows the public to legally own such products, etc. and affidavits from other friends and family who are prepared to testify that they know that you were in possession of the product in their state at prior times, dates, and places will usually result in the Judge ordering the Prosecutor to show some evidence as to how and where he thinks you got such an item In that Court's (State)Jurisdiction, and County of "venue". If he prosecutor can't make some showing, the charges are dismissed, and an order entered directing that your property be returned.
Its not unusual for some charges to be dismissed at the first appearance here. Prosecutors don't like cops with heavy badges very much, because they cause more problems than they solve. No one faults their passion, and honesty, but their judgment is questioned. You can't win them all- and officers are expected to be mature enough, and capable of self restraint enough, to let people go, even if they don't like it.
I can't count the times my clients' true offenses was being "mouthy" to an officer- what we called, " Contempt of Cop"--- when they were arrested and charged with some misdemeanor such as "disorderly Conduct," or "Resisting Arrest", when there is No underlying "offense" for which they were "resisting" arrest.
And, Just because possession of some animal product is illegal in one state does not permit state officials to SEIZE your property, when it was acquired in a state or jurisdiction where its Not illegal to kill or possess that animal product. They may not like people possessing Blue Bird feathers in Michigan, But that does not give them to right to seize your property if the feathers are acquired in some jurisdiction where its legal to have them.
There are certain animals protected by Federal law- such as Eagles, Condors, etc. where its illegal to possess any part of them, unless you have a special license- such as those given out to Native Indians. Federal laws apply in all states and Territories, unlike individual state laws.
DON'T CONFUSE THE TWO. If you paid attention to Nothing else in your Jr. High History classes, remember that the USA has both Federal and State jurisdictions, and that Federal Laws are limited in scope to those enabling powers enumerated in the Federal Constitution, and the Amendments thereto. State Courts are know as "Court of General Jurisdiction", while Federal Courts are known as "Courts of Limited Jurisdiction".