Respectfully, Ed, all the OP was asking is whether a ticking sound upon cold start is normal, to which the answer is "yes". It has nothing to do with the engine being "dirty". There is also no evidence to suggest the oil change interval or material specs have not been adhered to. The OP may be able to satisfy that question by simply asking the seller, checking what is displayed by the FSS, or viewing any available service records and then making a reasonable determination as to whether/when an oil change is indicated.