Yes, it's perfectly normal for a preschooler to print letters and words backwards.
Letters and words are really just squiggles on a page, to a preschooler. Your child is learning that certain squiggles on paper match his name. It doesn't really matter to him if there's a specific order to those letters. He hasn't learned that this is important yet.
His brain is getting trained to learn that letters have to be made in certain ways, that they need to be printed in certain sequences, and that those sequences make certain sounds.
You could play a silly game with him if you'd like. You could pronounce his name as he's printed it to show him that the letters need to be in a particular order. For example, if his name is "Glen" and he spells his name as "nelG", then you could pronounce it as /nelg/, and show him how to make his printing say /glen/.
You could put a green star, or green mark, on the page to show him where to start printing the first letter of his name. And you could put a red star at the end of his name. Or, you could draw an arrow on the page to show him which way to print his letters.
Usually, children learn the correct way to print and spell through many repetitions of printing letters and words in specific ways. These repetitions will happen at home and in preschool, kindergarten, and grade one. Gradually you'll notice fewer and fewer reversals of letters and words.
If you notice that your child continues to make a lot of reversals by the time he's in grade two, you can ask to have his reading, spelling, and writing development assessed by a reading specialist in your school system.
I hear your concern. With the information you have posted I understand you to say that your preschooler can properly wirte the indivdual letters but writes them backwards when printing his name. You didn't say if he always wrote letters backwards or if it was just his name. Writing letters backwayds may be a sign of dyslexia but at preschool age it is almost impossible to diagnose UNLESS he writes all his letters backwards all the time. Alot of beginning students do write some letters backwards, ie:d for b and p for q till at least into first grade. I would just keep watching him and if indeed he does write them all backwords all the time then prehaps speak to your pediatrician about your concern. It is usually into the 2nd grade before a teacher makes a recomendation to have a student checked for LD's. If it is just his name perhaps its a stage and he knows he gets your attention when he does it. Time will tell! Your on it, Mom. The answer will present itself.
Kid Angel Foundation
Nothing to worry about at this point. Reversals are common at this stage of development. Many preschoolers are quite adept at writing a mirror image of their name before learning how to do it properly. Reversals should lessen in frequency and be all but gone by the end of grade 2 as children have more practice with writing and using strategies to help differentiate between minimal difference letters and numbers such as b,d or 6,9. One example of a strategy for remembering the letters b,d is to draw a simple smiley face and put a pair of glasses on it (using the letters b,d of course) and call him Mr. b,d (Beady) eyes.