The distribution is not an IRA but rather another tax deferred retirement distribution from the Taxpayer's, not Spouse's, employee retirement plan.  

From my interpretation and the definition on the back of the 1099R, box 1 refers to an Early Distribution before 59 1/2.  Doesn't refer to what type of Early Distribution the release is coming from.  My experience would be that the IRA box would be checked if it was an IRA distribution.  

Thoughts?