Starting Lemon Thyme Seeds in September

We purchased a one gram package of your "Lemon Thyme Magic Carpet" seeds. Is it too late to start the seeds and then plant the seedlings this autumn? We planned on starting them in paper pots that we've made with your "potmaker". Would it be better to start the seeds in the spring and if so then approximately what month. Would the seeds still be viable in the spring?

My answer will have to depend heavily on the growing conditions you have both inside and outside of your house. Thyme is a high light plant and it does not like to dry out completely. The high light part is hard to meet in a house in the winter, unless you have some supplemental lighting. The not getting completely dry part is easier to meet in the house than outside if you live in a drought-prone area. Once the plants are mature and have deep root systems, the drought danger diminishes to almost nil, but young plants are a different story. So if you have a set-up with at least two 40-watt fluorescent tubes suspended just above the tops of the pots, go ahead and plant the seeds now. It will give you a good start for next year. But be sure to give the plants a cool rest of about a month once they are big enough to be less fragile. By cool I mean a temperature above but close to freezing. Watering will then be diminished as well, but not halted.
If you live in an area where you have short, mild winters, you could plant the seedlings out if they are about 3 months old. Be sure to mulch them well with straw once freezing weather starts. Mulching before frost would encourage mice to make their winter homes in the bed -not a good idea.
If you have to rely solely on windowsill culture, I would recommend that you wait till spring. Start your seeds about three months before your last frost date.
Store your seeds in the fridge, with a desiccant packet if the package has been opened.