diff --git a/c_gen/loxi_utils_legacy.py b/c_gen/loxi_utils_legacy.py
index e20155d..9abca52 100644
--- a/c_gen/loxi_utils_legacy.py
+++ b/c_gen/loxi_utils_legacy.py
@@ -180,6 +180,8 @@
     """
     Return True if cls_name is an instruction object
     """
+    if cls.find("of_instruction_id") == 0:
+        return False
     if cls.find("of_instruction") == 0:
         return True