CENTRAL & RIO GRANDE SW--It had been a year or two since I had gone to Lam's Chinese Restaurant for lunch.  Yet last Friday that was where I found myself.  The place was empty except for a table of men sitting in one corner.  They sounded like state workers.  Lam's has been a landmark for a working person's lunch for maybe twenty years.  It is on Central Ave. just west of Rio Grande, housed i…