In my best estimate, it is either 29450-1701 or 29450-1201, and more likely the 1201. But, I could easily be wrong. I haven't seen your engine and these things can be different. Sometimes substitutions are for a subclass or superclass.
One thing you can do is to pull yours and compare the dimensions and measurements to the figures shown for those two pumps, order the one that looks right, compare once you have it, and return and try again if wrong. You can also do the best you can from the outside and take a guess. You could also steer diesel parts direct to those two numbers and see what they can find focusing on them.
But, you can also see my many posts about these things. A lot of places have good prices drop shipping from manufacturers, but don't know the engines.
I buy most Perkins parts from S&W Diesel in Wilmington, CA (310-835-3155) and sometimes from Trans-Atlantic Diesel in Virginia (804-642-9296), because they know the engines and can solve problems. It is worth it to me to support their business and keep them doing that. S&W, in particular, has always been there to support me -- even when I haven't bought from them (in stock vs not vs time pressure).
It is also possible that Perkins sells the part under the original number to authorized dealers, by repackaging the correct substitute. I've seen S&W get Perkins to ship parts others said were unavailable, most recently an oil pressure relief valve. It showed up in Perkins wrapping and box printed with a Perkins number -- but had the same stampings (which didn't directly identify the manufacturer) as a 3rd party. The difference to me was that, lifting an engine to put it in was a big job, so I needed a perfect match, no guesswork the 1st time.
So, what to say? If it were me, and I needed to be able to pull it out of a box 5 years from now and know it was right because I was otherwise stranded, I'd call S&W (or transatlantic) -- with the added bonus of knowing that I'm keeping them able to do exactly that.
Other than using MrCool.us for coolers and heat exchanger (they took great care if me before I found S&W), I tend to be pretty loyal to S&W (and transatlantic, if dictated by shipping urgency).
But, it will be more expensive going through a legit over-the-counter storefront dealer, so I can also understand taking a stab at the cross yourself (I gave you my best two estimates) and verifying it (be prepared to make a gasket).
Sadly, without being there, I can't offer you a guarantee. I can just say that it would surprise me if I can find a match that S&W or transatlantic can't find. But, I won't give myself extra credit by comparison to an online-only, many, many line place like diesel parts direct.
Please don't get me wrong, I've never heard a bad word about diesel parts direct, never heard them ofvthem shipping a bad match or having high prices, etc. And, I really don't know that I have this right.
...just offering up my best from here.