No, it's not the original house, although I believe the front door frame was the only oirginal piece used in the reconstruction.
I went there in '88 and basically thought of it as an exaggerated reconstruction. But very inaccurate: the furnishings are quite nice, with cheery wallpaper etc, but from all accounts, the original house was nothing like that.
And the quality and amount of stuff in there was just ridiculous. The Presleys were poor, but the house doesn't really reflect that at all.
The records as to exactly where the original house stood disappeared long ago, when Old Saltillo Road (supposedly where the original house stood, but this is open to debate) disappeared due to rezoning.
The house is not an essential stop on anyone's US Presley pilgrimage, I think ...