I’m a 1:20.3 scale live steamer and familiar with the accucraft locomotive in question. That model locomotive is #499 and was done in the tri-color Moffat herald with a green boiler. Accucraft also offered the K-37 in three other Flying Grande numbers and all had the flared tenders discussed above. Keep in mind that the K-37s were rebuilds from earlier C-41 standard gauge locomotives. I just did a brief check of photos in the RGS/D&RGW Locomotive Pictorial Volume I by Grandt. While I did not find a flat sided tender on any of the K-37s pictured, I did find two different tender configurations: one with a small flare and a second type with the larger, complex flare more commonly seen on K-37s. So Accucraft may have gotten the tender wrong for that specific K-37 but they did appear to get the tender shape correct on the other 3 locomotive numbers. And I would suggest that one not condemn a manufacturer for having less detail than another company, because these two companies were building their models for entirely different audiences. We live steamers do like a good bit of detail, but unlike On3 modelers who may put their models on their layouts and keep them there, we need models that can be handled regularly and rolled over for service, cleaning and lubrication. Excessive amounts of detail on these latter models is just more stuff that can break off or snag a cleaning rag.
Ross Schlabach