I suggest you check into the rule that IRA’s cannot invest in collectibles, including metals like gold and silver bullion unless they are in the custody of a qualified trustee as described in Internal Revenue Code Section 408(m). Such investments are taxed as immediate distributions from your IRA. It appears to me that holding a PFIC stock that holds bullion may fall within this rule.
Correction: I was able to find out that holding gold/silver bullion in the PFIC form of ownership will NOT trigger the Sec 408(m) collectibles rule, so you don’t have to worry about that.