Do I need to arrive from Canada to get a TN?

I am currently working for a consulting firm in NYC, on an F-1 visa (optional practical training portion of my student visa), which runs out on July 1.

I am going to Panama on vacation in late-June, and flying back to JFK airport in early July to resume work under TN status. The company has prepared all my TN materials in order for me to continue working here.

My concern is whether I will be able to get the TN coming from a country other than Canada? I recently spoke by phone with border patrol officials who told me that it should be fine, as long as my paperwork is in order.

Thought I'd check to see if anyone here has done this, or has any advice on whether this is indeed possible/easy/anything to keep in mind?

Well, it's the FTO at the POE who does the entry, so I can't see that it would matter how you get to the POE.

Generally speaking any Class A POE will work.
But the fact that most TNs are granted at preclearance on either Canada and Mexico soil or border between Mex and US or Can and US. The FTO @ those borders have more experience. If you have a complicated situation like management consultant, a non US/ Canada degree, or any not straight forward things, you better off go through those borders from Canada.

Although theoretically, it shouldn't matter. But I am always skeptical about doing a TN through an inbound flight from else where other than Mex / Canada. For example, flying inbound from Asia or Europe, you will go through security check point on US soil (when your plane landed on US airport) and those guys do not normally take care of TN.

Does anyone have experience on getting TN through non Canada/Mexico border or Pre-clearance?