[Core][Bugfix] Accept GGUF model without .gguf extension (#8056)

vllm/transformers_utils/utils.py

@@ -0,0 +1,16 @@
+from os import PathLike
+from pathlib import Path
+from typing import Union
+
+
+def check_gguf_file(model: Union[str, PathLike]) -> bool:
+    """Check if the file is a GGUF model."""
+    model = Path(model)
+    if not model.is_file():
+        return False
+    elif model.suffix == ".gguf":
+        return True
+
+    with open(model, "rb") as f:
+        header = f.read(4)
+    return header == b"GGUF"