No, I can't find any markings at all. Tractor is a 2013 and I'm guessing these are the originals from when it was built. I have to go return these today and will take your information above with me. Thanks!
Goldsmith1, I'm right there with you when a decision involves cost savings. However, experience has taught me that for parts that are specific to the engine and its smooth running, it's more cost effective in the long run to purchase from a dealer that can supply OEM parts. Glow plugs should last a long time...if your 2013 has original glow plugs, for example so there's not much point on trying to "make do" on a part that may/may not be optimal.
And, speaking of costs...these dealers and parts houses have a lot of expense in keeping inventory. Plus, there is the employee/employee benefits cost, building and maintenance cost, insurance...on and on. They have to make a profit to stay in business. I'm thankful there are places that have what is needed when it is needed. So, some "extra" cost is part of the process. If the ordered part is right, everybody wins.
Messick's has proven itself, imho. I bought some wheels for my RCK60-22BX mower deck that didn't fit. They took them back and even paid for return shipping. If you ask for USPS delivery instead of FedEx, shipping will be a little less even though it seems like a lot. I don't think they try to profit on shipping. If you figure out the cost in time and fuel to go to a nearby parts store or dealer, buying online can be cheaper...if you know exactly the part that you want.
All this above info is provided at no charge.
I just wanted to chime in to encourage you. Regardless of how you access the correct glow plugs, I hope you get it done and get it right the first time. It's annoying to need a part and have to wait. Such is life, they say.
Tractor Gal