Rick,
I think its a freighter -either a -300 or maybe a very early -400 but the wingtips are obscured which would identify it. It could actually be a converted Singapore Megatop. Because of the engines and maintenance inspections of old crap like this they are put into scrapyards and anything of any worth is stripped out before the rest is converted into caravans and window frames. The quality of the aluminium ingots derived from these scrapyards is not something you really want to use again in an aeroplane in the future.
The higher performance 747 you mention might be the B747-SP which again are becoming very rare as nobody wants to re engine them. Indeed they had higher tailfin ( or vertical stabilizer) to counter the loss of an outboard engine at lower speeds, a shorter fuselage
(Which was the reason for the higher tailfin) [a mucher smaller lever moment of rudder deflection]. They were the favoured jet of the arab leaders but of course Boeing came up with -400 conversions with gold taps, jacuzzi's, ferrari garage in no 1 Hold, cinema, formal dining room, and even a little boys room. I'll leave you with that thought.
Qaboos bin Said (bin Taimur) has such a -400 and his previous was the -SP