Quite the opposite, actually. In fact, every "pre-order" ship I've ever ordered has arrived promptly, as if it was there all along. This is why I always refer to "pre-order" in "air quotes".
Now, having a rare grasp of the conspirator's mind, it is my theory is that, since most "pre-order" items (larger-size Specials and XL ships, specifically) are higher-dollar than regular ships, I found it interesting that the regular promotional codes that Eaglemoss regularly announces never apply to "pre-order" items. If they did, there would be some big savings to customers. Even after ships are very much available for months, they would often still be listed as "pre-order" for no apparent reason. Since most people agree that their site's architecture and maintenance level really aren't all that great, it could be easily rationalized as sheer laziness. I'm sure there's some of that going on, too. However, based on my own experience and the experiences of others, I am very much convinced that they keep things on "pre-order" longer than necessary to prevent people from applying these ostensibly generous promo codes on higher-dollar items. I also believe that this somewhat ethically gray-area of behavior is actually an active part of their "business model" (also in "air quotes").