If we refer back to the list of sources I posted on August 15th, 2013 above, they all categorize them nicely as Asiatic, Longiflorum Asiatic and so on. So if you order from them and baring any human error, you'll get what's described. However, when it comes to pre-packaged lily bulbs such as ones sold in big box stores and some others, this may not be the case. They (the wholesale distributors they buy from) have a tendency of lumping everything together, so to speak, so that anything Asiatic is called Asiatic, so it could be either. If the package has a lily name, that's good; then you can look it up in the lily registry at the above sticky thread or ask the question here whether it's an LA or not. In general, the best practice is to order from good reputable sources that differentiate between the two.
Longiflorum Asiatics are very sturdy and don't require staking generally. If you plant them in real sandy soil, you might want to plant them an inch or two deeper, that's all. Trumpets and most Oriental Trumpets would likely require staking in sandier type soil, however.
If you need a quick answer along the way, you can always ask it here.
Edit Added: There are no shorter LAs that I'm aware of.
