Thread 4 shrimp close together on each thin wooden skewer. Put oil and parsley in a small saucepan; heat just until bubbling, then remove sauce from heat. Place skewered shrimp on a rack in a pan; brush generously with garlic sauce. Broil shrimp 4 inches from heat until they turn bright pink (about 4 minutes). Baste at least once with garlic sauce. Turn and broil on other side about 3 minutes or until shrimp feel firm when pinched; baste once. (Or place skewers on a greased grill about 6 inches from hot coals. Cook and baste as directed for broiled shrimp.) Place each skewer on serving plate an lightly sprinkle with lemon juice. Serve with Guacamole.