I believe they have but not in a way which lines up their individual timelines. this is because i would suggest they have met in Ahnenerbe
Ahnenerbe is a shop with two entrances located beside a cinema, and it exists in multiple locations, often appearing and disappearing. It also appears as a regular shop within different series, such as in Fate, where it is located near the large bridge in Fuyuki City. There is a rumor that people who under normal circumstances cannot meet each other are able to meet inside. It is the frontier where the worlds of Tsukihime and Kara no Kyoukai meet. Shiki Tohno and Shiki Ryougi, and Arcueid Brunestud and Touko Aozaki, are all related people that cannot be inserted together in a formal time axis without causing inconsistencies in the workings of either world. When characters from different works meet in this shop, any time discrepancies are eliminated so that they can appear at the age that they were introduced.
aside from the location in Fuyuki i recall that is it also located in Misaki Town (location of Tsukihime) as
The menu includes strawberry pie recommended to Akira Seo by Fake Shiki for its fine taste
i recall in the Tsukihime PLUS-DISC story, "Alliance of Illusionary Eyes" this recommendation was the Fake Shiki taking Akira Seo to a coffee shop and having the pie.
Now as for when they could have entered Ahnenerbe. while there are times in Kara no Kyoukai and Tsukihime where Ryougi Shiki and Arcuied could just be wondering about and have entered off-screen, in regards to Saber's at the very most i don't recall her entering the coffee shop during her date with Shirou in the Fate Route of Fate/Stay Night and she she didn't go on any "dates" with Irisviel during Fate/Zero. haven't not played Fate/Hollow Ataraxia but understanding how it's played it's possible she may have went there off-screen during then since the Servants in Fate/Hollow Ataraxia have a bit more freedom around Fuyuki (ie. Lancer going fishing)