It's impossible to say, because even if all the units coming out of MS' factories are Jasper models, what really matters is what inventory your local stores have, or wherever you buy it from.
There are a number of articles out there for helping determine whether or not what you're getting is a Jasper or not. Read some of those, and armed with that info, you can start hunting through the stock at different stores. If you buy online, it's luck of the draw. They might have some unit that's been sitting around in a warehouse for over a year, or they might regularly turn over their inventory so that they generally have the latest models pretty quickly.
I don't think it will matter really. Aside from running a little cooler and using maybe 20W less energy on average, the RRoD issue more or less was resolved with the Falcon model. The problem now seems to be with optical drives that stop reading discs reliably. Personally, I've gone through 2 systems with that problem so far (fortunately within the warranty period) and I've seen plenty of other examples of people with the same problems. Which might be a part of why MS has moved to letting people buy games via Xbox Live, and download them directly to their consoles.
I know some Elites were still shipping with Falcon chipsets/mobos earlier this year, but with the latest Elite has MSFT finally gone through all of those 90nm GPUs? My early production 20GB 360 is finally giving up the ghost (but amazingly still no RROD, but a flailing HD along with degrading connector problems @ the back of the unit) and with the latest price drop it's probably time--or, more likely, an excuse--for an update.

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