Since it is flowering probably about the last 5 sets or so of leaves are not going to be at all diagnostic for what the plant might have been before flowering.
Based on the lower leaves they do not quite look like what most of us know as var. 'truncata'. However, that is potentially greatly influenced by a very limited number of tissue cultured exceptional clones (like the Huntington clone, etc). The relatively short rounded leaved versions are afaik not that typical in the wild. On top of that there is supposed to be great variation throughout the range of the plant with some of the more northerly versions looking a lot like parryi v. parryi. Add to that the potential for changes due to growing conditions and it may just be what var. truncata turns into if grown way outside its normally range.
If I saw this without it being labeled as A. parryi var. truncata it would not be the first thing I'd call it, but that said, it is not completely impossible for it to be var. truncata, just not one from the selections that are now mostly seen in the trade. I do not know if there are obvious differences flower wise that might help if there were flower pictures.
Is this the best picture to be the main picture showing up when the var. truncata entry comes up, I would say no, but that is about as far as I can go with this. Parryi is just a highly variable species even within each subsp./var. The one that stands out the most to me is subsp. neomexicana and this one is definitely not that.
BTW since we are on the topic of wrong IDs the two pictures by Fleur are definitely not Agave parryi more like kichiokan...
I'll see how they develop. Thanks for all the input and hope the question wasn't too much of a bother. 
