Concur, partly because nukes really are a "use 'em or lose 'em" prospect.
Let us assume, for the purposes of argument, that the nukes are real. If the nukes are the crude types used by Pakistan, the initiators are most likely polonium--and polonium initiators last about a week. After that they decay so badly that they generate a fizzle.
If the nukes are XUSSR, then they're a wee bit more modern, and use deuterium-tritium initiators. These last somewhat longer, but still need replacing after a few months, because the tritium decays to 3He2. This isotope of helium has an enormous appetite for neutrons; even very small amounts will cause a fizzle. We had (and, presumably, so did the Russians) many thermonuclear tests fizzle because of helium contamination in the 1950s.
BTW, tritium is VERY tightly controlled, because it costs about $50,000 an ounce on the open market. (The tritium in your watch dial or compass is a very tiny fraction of an ounce.)
In other words, once you have a nuke, unless you have adequate facilities for maintaining the nuke, you either use it, or it decays into uselessness in very short order.
Why do a 911 airplane attack when you have a nuc?
A few years back, I heard that the Iraqis got suckered by some Russian Mafiya types offering to sell them nuclear warheads, and that Saddam's folks got ripped off for 10-20 megabucks.
Do ya think maybe Osama fell for the pitch? :o)