Can syphilis symptoms of the throat be a white coating on the tongue and a layer on white stuff at the back of the throat ?

Not typical : Those are not typical symptoms one associates with syphilis. Syphilis and HIV testing can be done with a simple blood test at any doctor's office or public health clinic. White coating on the tongue is common in smokers and can be removed with a tooth brush or dental floss.

No: That said, you don’t want to wait if you think you have been exposed to any sexually transmitted disease. Early detection, via a simple blood test, is key to successful treatment. STDs are much easier to treat early. Please see your GPor seek evaluation at any health care facility.