Yes and no.
Already you can publish yourself on Windows/Netbook using tier 1 (basic), as the IDE wraps up the bytecode with the AppGameKit player into a single executable.
On other platforms however (OS-X, iOS and others), if you want to publish yourself using tier 1, you need to wrap up the bytecode AppGameKit produce with the applicable C++ source code for the AppGameKit engine to the intended target yourself. There are a few how-to guides to doing this both here on the forum and on youtube.
If the target is an Apple product (Mac, iPad, iPhone, iPod), you also need to compile your project on a Mac, using Apples' dev-tool/compiler and have an apple developer license that cost 100USD per year.
To save you this hassle, TGC are, as I've understood it, exploring and testing the option of tier 1 programmers submitting their projects to TGC who will then proceed to compile your project to all supported platforms _and_ publish them in the applicable app-stores on your behalf. TGC will then send you the revenue from sales of your project, after deducting a given percentage (30% i think) for the services rendered.
This saves you registering as a developer for the various platforms that require it, no need to buy platform specific hardware, no need to test on all supported hardware and so on.
Develop and test using tier 1 on PC. If you think your project got some profit potential and is up to given standards, submit to TGC who will then validate your project for you on all devices and then submit to relevant app stores.
When they will give us this option is not disclosed yet, but hopefully sometime soon
Until then, providing you got the means and know-how, it is perfectly possible for you to publish yourself using both tier 1 and 2.