Is bradycardia a problem when considering plastic surgery for a full facelift?

If this is physiological and a sign of an efficient cardiovascular system this might actually benefit you in facelifting. You should have the bradycardia looked at by a cardiologist beforehand though to exclude metabolic or cardiac causes. The main causal factor in facelifting complications, specifically haematoma is hypertension or high blood pressure. I agree that Local anaesthesia surgery reduces immediate complications associated with facelifting

Facelift surgery is often performed under IV sedation or general anesthesia. During these types of anesthetics you should be monitored by an anesthesiologist. At your age you should have a preoperative medical examination and work up prior to any elective surgery. Generally speaking having stable bradycardia is not a contraindication to facelift surgery. 

Bradycardia is not a problem if it is the result of being physically fit and your bradycardia is in normal sinus rhythm on your EKG. It is a problem if it is the result of an abnormal electrical conduction in your heart. A simple test to find out would be a 12-lead EKG. Other potential causes would be hypothyroid or medication effects. A careful history and examination will rule out all abnormal causes.